The seller has a pretty fair description and actually highlights the dial issues. You could ask for a few better pictures to assess if it has some further staining (the biggest issue being the missing marker it seems).
According to the description it could need a service, so you have to factor in 200-300£ in addition to the price to enjoy as a daily wearer. The BoR is around 200-250€. Assuming this goes at the BIN price, it’s not ridiculous I think, but up you to decide what you’re ready to put into this watch. With the service it will be hard to recoup later on.
Most here (I think) would advise to find a cleaner dial, these references being quite common. Difficult to “unsee” and fix these issues later.
